The present invention relates to a recording sheet reversing device of a two-sided copying apparatus.
Conventionally, two-sided copying apparatus are widely known in which, after an image has been recorded on the obverse side of a recording sheet, the recording sheet is fixed; the recording sheet is reversed and re-fed; and after an image has been recorded on the reverse side of the recording sheet, the recording sheet is fixed; and images are respectively recorded on both sides of the recording sheet. As the structure of the two-sided copying apparatus, after the image has been recorded on the obverse side of the recording sheet, the recording sheet is fixed, the recording sheet is reversed by a recording sheet reversing mechanism, and the recording sheet is temporarily accumulated in an accumulating section. Next, the accumulated recording sheet is successively conveyed to a transfer section, and after the image has been recorded on the reverse side of the recording sheet, the recording sheet is fixed and delivered.
In such the two-sided copying mechanism, a mechanism by which the recording sheet is reversed and re-fed, can be formed into a small size, and thereby, even when it is housed in the copying apparatus, it does not require a large space. However, a mechanism of the accumulating section in which the recording sheet is temporarily accumulated after the recording sheet has been reversed and re-fed, is difficult to be smaller, and it is necessary to provide a large space in the copying apparatus so that the accumulating section is housed.
Further, the copying apparatus itself temporarily stacks and accumulates the recording sheet on a stacking section for the recording sheet, and re-feeds the recording sheet from the stacking section, and thereby, the image, recorded already on a one side of the recording sheet, adheres to other recording sheets and stains the recording sheets, or the recording sheets adhere to each other and cause double-sheet feeding when the recording sheets are re-fed, and thereby jamming easily occurs, which are disadvantageous.
Accordingly, there is a drawback in which the overall size of the apparatus becomes larger. Then, as a mean to provide the accumulating section of the recording sheet without increasing the size of the copying apparatus, a means is proposed in which a portion of a sorter, which is mounted onto a sheet delivery section, is utilized, and an accumulating section on which the recording sheet is accumulated, is provided. As the means, Japanese Utility Model Open to Public Inspection No. 166248/1984, Japanese Patent Publication Open to Public Inspection Nos. 109071/1986, and 130128/1986, are widely known. As described above, an increase of the overall size of the copying apparatus is prevented by utilizing the sorter position.
As described above, when a two-sided copying mechanism is provided in the copying apparatus, and the recording sheet reversing mechanism and the recording sheet accumulating mechanism are housed in the apparatus, the overall size of the copying apparatus becomes large. Accordingly, as described above, a means by which a portion of the sorter position is utilized and the accumulation section of the recording sheet is provided, and the recording sheet is reversed, should be essentially provided in the copying apparatus. In this case, the customer who does not always need the sorter, is obliged to purchase a useless apparatus. Further, because a portion of the sorter is utilized, the number of sheet delivery trays for the sorter to be provided, should be reduced, resulting in reduction of the number of sets of recording sheets to be delivered.
Accordingly, in the case of a copying apparatus in which the sorter is not used, only the recording sheet accumulating section is provided outside the apparatus, and therefore, the size of the overall structure of the copying apparatus can not be reduced.